1. Field of the Invention
The present invention relates to a recording and/or reproducing apparatus and a method of controlling such a recording and/or reproducing apparatus. More particularly, the present invention relates to a recording and/or reproducing apparatus for intermittently recording and/or reproducing data.
2. Background of the Invention
There are known a reproducing apparatus for reproducing recorded data from a magneto-optical disc and an optical disc and a recording apparatus for recording data on a magneto-optical disc.
For reproducing data from or recording data on such an optical recording medium, an optical head radiates a light beam to the recording surface of the optical recording medium and detects a light beam reflected by the optical recording medium to reproduce the data recorded on the optical recording medium, or radiates a light beam to the recording surface of the optical recording medium to record desired data thereon. It is the customary practice to effect tracking and focusing servo control on the optical head for controlling the light beam to scan the recording surface properly.
The gain of a tracking or focusing servo control circuit, i.e., the gain of a tracking error signal or a focusing error signal generated by the tracking or focusing servo control circuit, has to be adjusted to an appropriate level for good servo control depending on the recording or reproducing apparatus.
The adjustment of the servo control signal gain results in adjustments of servo control characteristics such as servo control responses and shock resistance to respective states, so that suitable servo control characteristic states can be selected depending on how the apparatus are used, the environment in which they are used, and the disc used in the apparatus.
Heretofore, the servo control signal gain has been adjusted by varying the feedback resistance of an operational amplifier through adjusting a semifixed resistor during an adjustment process after the recording and reproducing apparatus have been manufactured. If a recording or reproducing apparatus is equipped with an automatic servo control signal gain adjusting circuit, then the servo control signal gain is automatically adjusted when no reproduced audio signal is outputted, e.g., immediately after an optical recording medium such as an optical disc has been loaded, or when no recording signal is inputted.
Actually, the servo control signal gain cannot be adjusted to a suitable level unless adjusted based on various conditions including the environment in which the recording or reproducing apparatus is used by the user, the disc itself for recording and reproducing data, the ambient temperature at which the recording or reproducing apparatus is used, the scanned position on the disc, i.e., the positional difference between radially inner and outer regions on the disc, and the aging of the disc and the apparatus. Since the servo control signal gain is adjusted only once by the semifixed resistor before the apparatus is shipped from the factory, however, the servo control signal gain is adjusted based on the above various conditions.
If the recording or reproducing apparatus is of the automatic servo control signal gain adjusting type, then the servo control signal gain can be adjusted based on those conditions that include the ambient temperature at which the disc is loaded. However, it is impossible to adjust the servo control signal gain to an optimum level based on other conditions including temperature changes during a subsequent reproducing or recording process and the positional difference between radially inner and outer regions on the disc.
If the servo control signal gain is not set to an optimum level, then the recording or reproducing capability of the apparatus is lowered by vibrations, disc scratches, surface fluctuations, disc eccentricities, etc.
One solution would be to effect automatic servo control signal gain adjustment during a reproducing process, for example. However, the automatic servo control signal gain adjustment during a reproducing process would requires a sine-wave signal to be added as an adjustment reference to the servo control signal, resulting in a reduction in the servo control capability. Therefore, a track jump would easily occur due to scratches or vibration, frequently causing a skip in the reproduced sound. For this reason, it is not preferable to carry out the automatic servo control signal gain adjustment during a reproducing process.